Dry cleaner fluid circuit



y 1966 D. 1.. LANG ETAL 3,250,098

DRY CLEANER FLUID CIRCUIT Filed Feb. 12, 1964 2 Sheets-Sheet l EL D I n J 24/ g E TORNE YS y 10, 1965 D. L. LANG ETAL 3,250.098

DRY CLEANER FLUID CIRCUIT Filed Feb. 12, 1964 2 Sheets-Sheet 2 fcy- 3 g u 5- g 5.4 Li. 29 J W N w g b l .53 37 Z7 Z7 77 267m 50 46 39 0407 M V INVENTOR.

TORNEYS United States Patent 3,250,098 DRY CLEANER FLUID CIRCUIT David L. Lang and Michael J. Bottas, St. Joseph, Mich., assignors to Whirlpool Corporation, Benton Harbor, Mich., a corporation of Delaware Filed Feb. 12, 1964, Ser. No. 344,406 11 Claims. (Cl. 6818) This invention relates generally to an improved form of dry cleaning apparatus and more particularly relates to an improved fluid circuit for the apparatus.

A principal object of the invention is to provide an improved fluid circuit for a dry cleaning apparatus arranged with a view toward increasing the efiiciency of the apparatus and preventing the flow of unfiltered fluid to the cleaning apparatus.

A further object of the invention is to improve upon the fluid circuitry for dry cleaning apparatus in which cleaning solvent is filtered and condensed and run through a carbon bed, by so arranging the fluid connections as to prevent the passage of unfiltered solvent to the cleaning apparatus and through the carbon bed.

Still another object of the invention is to provide an improved form of dry cleaning apparatus and fluid circuitry therefor having a filter, condenser, cleaning zone and carbon bed, in which the flow of filtered solvent is maintained through the condenser and to the cleaning zone by splitting the fluid flow from the filter to eifect the flow of the filtered fluid to the condenser and cleaning zone, and clogging of the carbon bed is prevented by directing the filtered fluidto the carbon bed downstream of the split connection to the condenser and cleaning zone.

A further object of the invention is to improve upon the fluid circuitry for dry cleaning apparatus of the type in which solvent is sprayed on clothes tumbledin a tumbling drum and is condensed in a condenser and filtered prior to the condensing operation and is run through an activated carbon bed after the cleaning operation, in which the supply of filtered solvent to the tumbling drum and carbon bed is assured by supplying solvent to the condenser and tumbling drum after filtering of the solvent and by-passing fluid from the tumbling drum to the condenser upon predetermined pressure conditions indicated by clogging of the filter.

Still another object of the present invention is to provide a fluid flow system for a dry cleaning apparatus assuring that clean solvent be restored to the solvent tank for the apparatus and preventing the passage of unfiltered solvent to the cleaning apparatus and the carbon bed therefor, all under 'the control of a programmed sequence of automatic cleaning and extraction periods.

These and other objects of the invention will appear from time to time as the following specification proceeds and' with references to the accompanying drawings wherein:

FIGURE 1 is a fluid diagram of a fluid flow system for dry cleaning apparatus constructed in accordance with the principles of the present invention;

FIGURE 2 is a program chart indicating the program- 3,250,098 Patented May 10, 1966 ice The drum 10 may be rotatably driven about a horizontal axis at tumbling and extracting speeds through a motor 12 and suitable drive and change speed gearing (not shown) driven therefrom.

The tumbling drum 10 has an open forward end portion 13 through which cleaning solvent is injected into the clothes through a solvent conduit or line 15. The conduit 15 enters the casing 11 defining a cleaning zone at an upwardly inclined angle, to inject solvent into the clothes into the tumbling drum under pressure and may have a nozzle (not shown) at the terminal end thereof, to provide the required jet or spray to penetrate the clothes tumbled within said tumbling drum. The casing 11 has a sump 16 having a pipe 17 leading therefrom into a solvent tank 19.

The casing 11 also has an air duct 20 leading therefrom intermediate the ends thereof into a housing 21 for a condenser 23. A suction blower 24 having its inlet in association with the interior of the housing is provided to draw air and vapor from the casing 11 and circulate the air back into said casing, through a duct 25 entering said casing adjacent the upper end thereof. A motor 26 is provided to drive the blower 24 in a conventional manner. The air duct 25 has two air valves 27, 27 therein. The air valves 27, 27 maybe maintained closed as shown by the solid lines by a single solenoid (not shown) and may open as shown by the dotted lines upon deenergization of the solenoid to divert air to the atmosphere. A resistor heater 29 is provided in the pipe 25 within the housing 11 to heat the air entering said housing during the extracting and drying operation.

The housing 21 has a drain line 30 leading from the bottom thereof and draining any solvent brought into said housing through the air duct 20 and condensing in said housing, back to the solvent tank 19.

The solvent tank 19 has a refrigerating unit 31 therein for maintaining the temperature of the solvent to the required temperature. The solvent tank also has a partition 32 spaced relatively close to the end of said tacnk opposite from the pipe 17, and stopping short ofthe bottom of said tank. A precoat dispenser 33 for supplying a filter coating, such as, diatom-aceous earth, to coat tubes 35 of a filter 36, is mounted on the top of the solvent tank '19 between the end of said tank and the partition 32 to discharge a filter coating material into the tank. A motor37 is provided to drive the precoa-t dispenser 63-,

The filter as may be a well known form of diatom aceous earth filter in which the diatomaceous earth collects on the filter tubes 35. The filter tubes 35 are foraminous or porous and are so mounted that all of the solvent passing through the filter passes through the filter tubes. The filter 3 6 may be of a conventional form so need notberein be shown or described further. A dump valve 39 leads from the bottom of the filter and is connected with a sediment trap 40, disposed therebeneath and having a removable filter basket or container 41, trapping the seidiment. The basket 41 is periodically removed and emptied for residual solvent recovery after a .certain number of cleaning cycles. The dump valve 3-9 may be solenoid operated and may be opened upon the energization of its solenoid (not shown) during the deodorizin-g cycle.

An intake pipe 43 leads along the bottom of the taruk 19 from the compartment formed between the end of the solvent tank and the partition .32, beneath the precoat dispenser 33, to a pump 45 suitably driven from a motor 46 on the outside of the solvent tank 19. The pump 45 has a pressure line or conduit leading-upwardly therefrom into the casing for the filter 36 .on the upstream side of the filter tubes 35. A check valve 47 is provided in. the pressure line 80 to prevent the back flow of fluid into said solvent tank during the operation of back washing the filter.

it A pressure line or conduit 48 leads upwardly from the filter 36 and splits or branches into a pressure line 49 having a valve 50 therein communicating with the pressure line 15. The valve 50 may be a solenoid operated valve of a well known form and will hereinafter be termed a wash valve. The pressure line 48 leads upwardly from the branch pressure line 49 into the housing 21 and has communication with the condenser 23. A check valve '51 is provided in the conduit 48 downstream of the branch pressure line 49. The condenser 23 discharges solvent into a return line 53 leading to the solvent tank 1'9. The pump 45 thus picks up the solvent and coating agent and pumps the solvent and coating agent upwardly through the conduit 80 and through the filter tubes 35, depositing the coating agent on said filter tubes. The valve 50 is closed during this operation, as is a carbon tower solenoid valve 55, communicating with a carbon tower 56 having a carbon bed therein. The filtered solvent thus passes upwardly along the pressure line 48 and upwardly through the solvent condenser 23, where it is returned back to the solvent tank through the return line or conduit 53. The necessary back pressure for establishing the precoat on'the filter tubes 35 is attained by the normal flow restriction of the coils in the solvent condenser 23. The solvent is circulated from the tank 19 through the filter 36 and condenser 23 back to .the tank 19 for a predetermined time, which may be three minutes, at which time an adequate filter coating is established on the filter tubes 3-5.

The washing operation may then be started by opening the wash valve 50 to effect the injection of solvent in the clothes in the perforate tumbling drum 10. During the washing cycle solvent is routed through the condenser 23 as well as through the perforate drum 10.

Solvent is routed through the carbon tower 56 and carbon bed therein after the washing cycle by closing the wash solenoid valve 50 and opening the carbon tower solenoid valve 55. Solvent passing through the carbon tower and carbon bed is returned to the solvent tank 1 9 through a return line 57. A restriction 59 is placed in an'inlet line 60* between the valve 5 and the carbon tower 56. The restriction 59 forms a flow control orifice to force a part of the solvent through the condenser 26 to condense the solvent from the drying air circulated through the housing 2.1 by the blower 24 and to accommodate the rest of the solvent to be clarified by passing through the carbon tower 56. The carbon bed within the carbon tower 56 may be a bed of granulated activated carbon and clarifies the solvent in a conventional manner, so need not herein be shown or described further.

A by-pass line 61 is connected from the pressure line 80 upstream of the check valve 47 to the pressure line 48 downstream of the check valve 51 and the branch pressure line 49. A pressure relief valve 63 is provided in the bypass line 61toopen and accommodate the flow of fluid through said by pass line into the conduit 51 and through the condenser 23, when the pressure in the conduit 80 may build up'due to clogging of the filter tubes, caused by"'a dirty wash load.

It should here be noted that by bypassing the filter 36 and returning the by-passed solvent back to the tank 19 throughth'e condenser 23, no dirty solvent can be routed through the carbon bed since check valve 51 will prevent the back flow of unfiltered solvent through conduit 49 to carbon bed 56. All solvent must be first filtered before passing through the carbon bed, to thereby prevent the carbon bed from becoming clogged with dirt and filter agent particles or the flow of unfiltered solvent to the casing 11 during the washing operation, as frequently occurs in present day dry cleaning systems.

After the drying operation is complete there is no need to circulate solvent through the condenser to condense the solvent vapor from the drying air, the pump motor 46 is deen'ergized and the pumping operation is stopped. The dump valve 39 is then opened and the solvent in the system may backwash the filter tubes 35 to remove the filtering agent from the tubes and put the tubesin condition for a next succeeding cleaning cycle.

A pipe or conduit 65 is connected from the conduit 49 to the solvent tank 19 and has a check valve 66 therein, preventing the back flow of solvent to the tank 19, but providing air to the pressure line 49 during the backwashing operation of the filters.

Referring now in particular to FIGURES 2 and 3, illustrating the sequence of operation of the apparatus, in FIGURE 3 main line conductors 69 and 70 are connected with a source of electric energy to energize the various motors and valves in their predetermined sequences to effect the various cleaning operations generally described in the foregoing.

The refrigerating unit 31 is connected between the conductors 70 and 69 and energized under the control of a thermostat 71, which may be adjustable to maintain the temperature of the solvent at a predetermined desired temperature range.

A switch 72 is connected in the conductor 69 and may be a door switch, closed upon closing of the cleaner door. A cam operated switch 73, which may be manually operated, is provided to close a circuit through the conductor 69 and energize a timer motor 75 and a main drive motor 12 for driving the tumbling drum 10. The timer motor 75 drives a series of timer cams C1, C2, C3, C4, C5, C6, C7, C8, C9 and C10, each of which operates an associated switch to control the cleaning operation in a selected sequence. Upon energization of the timer motor 75, the timer cam C10 will be rotated to first close its associated switch and energize the dispenser motor 37, to etfect the dispensing of filter coating into the solvent tank 19 in the proximity of pump intake pipe 43. The timer cam C6 will then close its associated switch and energize the pump motor 46, to drive the pump 45 and circulate solvent with filter coating material through the filter tubes 35. At this time the switches associated with the timer cams C3 and C8 will be open and the wash valve 50 and carbon tower valve 55 will be closed. The solvent with the filter precoating agent will then be circulated through the condenser 23 back to the solvent tank 19, until the filter tubes 35 are sufficiently coated to efficiently filter the solvent, as it passes to the tumbling drum 10.

At the termination of the precoating cycle, the timer cam C3 will close its associated switch and energize the solenoid for the wash valve 50, and open said valve. Cleaning solvent will then be injected into the tumbling drum It) on to the clothes or other material therein. Toward the termination of the washing cycle, the timer cam C8 will close its switch to energize the solenoid for the carbon tower valve 55, to open said valve. Part of the filtered solvent will then pass through the carbon tower. Filtered solvent also will continue topass through the condenser 23. Since the resistance to flow is much less in the fluid path to the cleaning zone 11 than through the condenser 23, the majority of the solvent will flow through the materials in the drum 10.

After the washing cycle, the timer cam C3 will open its switch and effect closing of the Wash valve 50. The carbon tower valve 55' will remain open and the machine will go into its extracting cycle. At the initiation of the extracting cycle, the timer cam C7 will close its switch and a spin control 77 will come into operation to increase the speed of the tumbler drum 10 and to effect the driving of said drum at a speed sufficient to extract solvent from the clothes therein. The spin control 77 may be a conventional form of speed change mechanism or transmission capable of changing the speed of operation of the drum 10 from a tumbling speed to a centrifuging speed, and may be operated by the energization of a suitable solenoid (not shown) in a conventionalmanner, and no part of the present invention so not herein shown or described further.

During the extracting period all of the circulating solvent passes through the filter tubes 35 and part of the solvent passes upwardly to the condenser 23 and upwardly through said condenser and is returned to the solvent tank 19. Another part of the solvent passes through the con duit 49 and valve 55 through the carbon tower 56, it being understood that the quantity of solvent passing through the carbon tower is regulated by the flow control restriction or orifices 59, thereby also regulating the quantity of solvent passing through the condenser 23.

At the termination of the extracting cycle, the timer cam C5 will close its switch to energize the blower motor 26. The timer cam C2 will also close its switch to energize the air heater 29. The blower 24 will then draw air from the casing 11 through the air duct 20 and return the air into the casing through the air duct 25, the air being heated by the heater 29 and it is returned to the casing, to preheat the system and shorten the drying period. Also at the completion of the extracting cycle the timer cam C7 will open its switch and effect the shifting of the spin control to a normal tumbling speed. The air valves 27 will remain closed and the air heater 29 will be energized for the entire drying operation to promote drying of the clothes in the tumbling drum 10. The carbon tower valve 55 will remain'open and the blower motor 26 will be energized to circulate air around the heater 29 through the casing 11 and tumbling drum 10. The pump motor 46 will also remain energized and pump solvent through the filter 36 and upwardly along the pressure line 48 through the condenser 23 and through the carbon tower valve 55 to pass into the carbon bed under the control of the restricted orifice 59, providing sufficient back pressure to assure the passage of solvent into the condenser 23.

The cool solvent circulating through the condenser during the drying period serves to condense any solvent vapor from the drying air to be returned to the solvent tank 19 through the drain line 30. The filtering and return of the solvent and the clarifying of the solvent by passing through the carbon bed continues to the termination of the drying operation.

If at any time during the dry cleaning operation the filter tubes 35 should become clogged due to an excessively dirty wash load, the solvent will be by-passed around the filter 36, through the condenser 23 and to the solvent in which our invention may be embodied, it may readily be understood that various variations and modifications 1 in the invention may be attained without departing from tank 19. The check valve 51 will prevent the flow of the unfiltered solvent to conduit 49, thus preventing the passage of the contaminated solvent through the materials in the drum 10 or through the carbon bed 56. In the present invention even though the filter tubes may become clogged, the dry cleaning apparatus will continue through adrying cycle with the condenser 23 operative; therefore, thematerials would be dry and could be removed from the drum at the end of the programmed cycle.

At the termination of the drying operation the timer cam C8 opens its associated timer switch to effect closing of the carbon tower valve 55. The timer cam C9 then closes its switch to effect opening of the dump valve 39 and the back Washing of the filter tubes bythe solvent left in the system, to thereby place the tubes in condition for a next succeeding washing cycle. The main drive motor 12 continues in operation as does the blower motor 26. The timer cam C4 then opens its switch to deenergize the solenoid closing the air valves 27 as shown in the dotted line position and accommodate said air valves to open and by-pass the, air to the atmosphere and thus remove undesirable odors from the load in the tumbling drum 10, g

It should here be understood that the fluid flow system of the present invention may employ a so-called charged type of dry cleaning solvent in which the solvent includes a suitable quantity of detergent, for example, one to four percent. Since the detergent is completely soluble in the dry cleaning solvent, it is not filtered out and, accordingly, a rinse cycle is not needed, thereby permitting the system to go directly from a Wash to an extraction cycle.

While we have herein shown and described one form the spirit and scope of the novel concepts thereof, as defined by the claims appended hereto.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A fluid circuit for dry cleaning apparatus comprising, a solvent tank, a filter downstream of said solvent tank, a condenser downstream of said filter, a cleaning zone, a pump supplying solvent to said filter and to said condenser and cleaning zone, a carbon bed having a drain leading to said solvent tank, split flow fluid pressure lines leading from said filter and splitting the flow of fluid from said filter to said condenser and said cleaning zone, a valve in one of said fluid pressure lines leading to said cleaning zone, a fluid line leading from said one of said fluid pressure lines upstreamof said valve, and communicating with said carbon bed for supplying filtered solvent thereto, and a restriction in said fluid line leading to said carbon bed, to effect the flow of part' of the filtered solvent through said condenser and the balance of the filtered solvent through said carbon bed upon the closing of said valve.

2. In a fluid circuit for dry cleaning apparatus, a cleaning zone, a solvent tank, a drain from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat said filter to filter the solvent passing therethrough, a carbon bed draining to said solvent tank, a condenser having a drain leading to said solvent tank, split flow fluid pressure lines leading from said filter to said condenser and said cleaning zone, a fluid connection from said one of said lines leading from said cleaning zone to said carbon bed, a valve in said one of said lines leading to said cleaning zone upstream of said cleaning zone and downstream of said fluid connection to said carbon bed, and a restriction in said line leading to said carbon bed, to effect the flow of part of the filtered solvent through said condenser and the balance of the filtered solvent through said carbon bed.

3. In a fluid circuit for dry cleaning apparatus, a cleaning zone, a solvent tank, a drain from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat said filter, a carbon bed drainingto said solvent tank, a condenser having a drain leading to said solvent tank, and means transmitting filtered solvent to said condenser and said carbon bed and preventing the flow of unfiltered solvent through said carbon bed comprising split flow fluid pressure lines leading from said filter to said condenser and said cleaning zone, a fluid connection to said carbon bed from one of said lines leading to said cleaning zone, a valve in said fluid connection, a restriction in said fluid connection,

and another valve in said one of said lines downstream of said fluid connection to said carbon bed and etfecting the selective direction of filtered solvent to said cleaning zone and to by-pass said cleaning zone and flow through said carbon bed.

4. In a fluid circuit for dry cleaning apparatus, a cleaning zone, a solvent tank, a drain from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solventtank to said filter to coat said filter, a condenser having a drain leading to said solvent tank, split flow fluid pressure lines leading from said filter to said condenser and said cleaning zone, a check valve in said pressure line leading to said condenser, downstream of said pressure line leading to said cleaning zone and a by-pass line by-pass ing said filter and having connection with said fluid pressure line connected with said condenser upstream of said check valve, and having a pressure relief valve therein and by-passing the flow of fluid to said filter and directing the flow of fluid through said condenser upon the clogging of said filter caused by an abnormally dirty wash load.

5. In a fluid circuit for dry cleaning apparatus including a cleaning zone, a solvent tank, a drain from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat said filter, a carbon bed draining to said solvent .tank, a condenser having -a drain leading to said solvent tank, split flow fluid pressure lines leading from said filter to said condenser and to said cleaning zone, valve means in said fluid pressure line leading to said cleaning zone, a fluid connection to said carbon bed from said line leading to said cleaning zone and upstream of said valve, and a bypass line having a pressure relief valve therein, by-passing the flow of fluid through said filter and directing the flow of fluid through said condenser upon the clogging of said filter caused by an abnormally dirty wash load, and preventing the flow of unfiltered solvent through said carbon bed.

6. In a fluid circuit for dry cleaning apparatus, a cleaning zone, a solvent tank, a drain from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat said filter, a carbon bed draining to said solvent tank, a condenser having a drain leading to said solvent tank, a split flow fluid pressure lines leading from said filter to said condenser and said cleaning zone, a line leading from the fluid pressure line leading to said cleaning zone, and connected with said carbon bed for directing solvent to said carbon bed, and two selectively operable valves one being downstream of said connection to said carbon bed and the other being in said connection to said carbon bed and operable to effect the direction of solvent through said carbon bed and to bypass said carbon bed and pass to said cleaning zone.

7. In a fluid circuit for dry cleaning apparatus, a cleaning zone, a solvent tank, a drain leading from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat said filter, a carbon bed draining to said solvent tank, a condenser having a drain leading to said solvent tank, split flow fluid pressure lines leading from said filter to said condenser and said cleaning zone, a line leading from the fluid pressure line leading to said cleaning zone and leading to said carbon bed, two selectively operable valves, one being downstream of said connection to said carbon bed and the other being in said fluid connection to said carbon bed, said valves effecting the direction of solvent through said carbon bed and to said cleaning zone, and a hy-pass line having a pressure relief valve therein and connected with said pump and bypassing said filter and having connect-ion with said condenser to lay-pass solvent from said filter through said coning to said solvent tank, a condenser having a drain leading to said solvent tank, split flow fluid pressure lines leading from said filter to said condenser and said cleaning zone, a line leading from the fluid pressure line leading to said cleaning zone and connected with said carbon bed for directing solvent to said carbon bed, two selectively operable valves, one being downstream of said fluid connection to said carbon bed and the other being in said connection to said carbon bed, and a restriction in said line leading to said carbon bed, to effect the circulation of part of the solvent through said condenser and the balance of the solvent through said carbon bed upon the closing of said valvedownstrearn of said fluid connection leading to said carbon bed, and the opening of said valve in said fluid connection to said carbon bed.

9. In a fluid circuit for dry cleaning apparatus, a cleaning zone, a solvent tank, a drain from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat'said filter and filter the solvent passing therethrough, a carbon bed draining to said solvent tank, a condenser having a drain leading to said solvent tank and including a housing, an air duct leading from said cleaning zone to said housing and a blower effective to draw air and vapor from said cleaning zone to said housing to effect a drying operation, split flow fluid pressure lines leading from said filter to said condenser and said cleaning zone, a fluid connection from one of said fluid lines leading from said cleaning zone to said carbon bed, a valve in said one of said fluid lines upstream of said cleaning zone and downstream of said fluid connection to said carbon bed, and a restriction in said fluid connection leading to said carbon bed to effect the circulation of part of the solvent through said condenser and the balance of the solvent through said carbon bed upon the closing of said valve, and assure the condensing of vapor drawn from said cleaning zone into said condenser housing during the drying operation.

10. A fluid circuit for dry cleaning apparatus comprising, a cleaning zone, a condenser housing having a condenser therein, an air duct leading from said cleaning zone to said housing, another air duct leading from said housing to said cleaning zone and a blower circulated air and vapor from said cleaning zone through said housing and back to said cleaning zone, a solvent tank, a drain from said cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat said filter, a carbon bed draining to said solvent tank, a drain leading from said condenser housing to said solvent tank, split flow fluid pressure lines leading from said filter, one of said lines leading to said cleaning zone, another of said lines leading to said condenser, a line leading from said one of said lines to said carbon bed, two selectively operable valves, one being in said one of said lines downstream of said connection to said carbon bed and the other being in said fluid line to said carbon bed, said valves effecting the direction of solvent through said carbon bed and to said cleaning zone, a by-pass line having a pressure relief valve therein and connected with saidpump and by-passing said filter and having connection with said condenser to by-pass solvent from said filter upon the clogging of said filter and to assure that unfiltered solvent will not pass to and clog said carbon bed, and a restriction in said line extending to said carbon bed, to effect the flow of part of the solvent through said condenser upon a drying operation, to condense solvent from the vapor drawn into said housing by said blower during a drying operation.

11. In a fluid circuit for dry cleaning apparatus, a cleaning zone, a solvent tank, a drain leading from said 9 cleaning zone to said solvent tank, a filter precoat dispenser dispensing a filtering medium to said solvent tank, a filter, a pump communicating with said solvent tank and with said filter for pumping filtering medium and solvent from said solvent tank to said filter to coat said filter, a carbon bed draining to said solvent tank, a condenser having a drain leading to said solvent tank, a first fluid line leading from said filter to said condenser, a second fluid line connected to said first fluid line leading to said cleaning zone, a check valve disposed in said first fluid line downstream of said second fluid line connection, a third fluid line connected to said second fluid line leading to said carbon bed, two selectively operable valves, one of said selectively operable valves being in said second fluid line downstream of said connection of said third fluid line, and the other being in said third fluid line, and a by-pass line having a pressure relief valve therein and connected with said pump and by-passing said filter and 10' 1 connected to said first fluid line downstream of said check valve to by-pass solvent from said filter through said condenser upon the clogging of said filter to prevent the passage of unfiltered solvent to said carbon bed.

References Cited by the Examiner UNITED STATES PATENTS 3/1937 Angelus et a1 6818.l 12/1962 Boswinkle et a1. 68l8.1 X

OTHER REFERENCES Mark II Coin-Operated Dry Cleaner, Whirlpool, 1962, 6 pages.

WALTER A. SCHEEL, Primary Examiner.

WILLIAM I. PRICE, Examiner. 

1. A FLUID CIRCUIT FOR DRY CLEANING APPARATUS COMPRISING, A SOLVENT TANK, A FILTER DOWNSTREAM OF SAID SOLVENT TANK, A CONDENSER DOWNSTREAM OF SAID FILTER, A CLEANING ZONE, A PUMP SUPPLYING SOLVENT TO SAID FILTER AND TO SAID CONDENSER AND CLEANING ONE, A CARBON BED HAVING A DRAIN LEADING TO SAID SOLVENT TANK, SPLIT FLOW FLUID PRESSURE LINES LEADING FROM SAID FILTER AND SPLITTING THE FLOW OF FLUID FROM SAID FILTER TO SAID CONDENSER AND SAID CLEANING ZONE, A VALVE IN ONE OF SAID FLUID PRESSURE LINES LEADING TO SAID CLEANING ZONE, A FLUID LINE LEADIG FROM 